Sublimation refers to a physical purification process. A solid or crude material is placed in a vessel and heated under vacuum. Under sub-atmospheric pressure and controlled heat, a purified fraction of the compound changes directly from the solid to a vapor. By actively or passively cooling a discrete section of the surface of the vessel through which the vapor passes, the purified fraction of the compound can be condensed onto a collector surface while lower volatility impurities are substantially left behind. After the heat source is removed from the vessel and the vacuum is released, the sublimed compound can be collected from the collector surface. This process is usually performed with a sublimation apparatus. Unfortunately, conventional sublimation apparatuses have drawbacks in design.
FIG. 1 illustrates an example of a conventional sublimation apparatus. The illustrated conventional sublimation apparatus includes two main body portions: a sublimation chamber 10 and a coolant line assembly 12. The sublimation chamber 10 has a tubular shape and has a closed end 14 and an open end 16 such that the sublimation chamber 10 resembles a test tube. The coolant line assembly 12 includes a joint member 18 that reversibly fits into the open end 16 of the sublimation chamber 10. Coolant is circulated through the coolant line assembly 12 via outlet and inlet ports 20, 22. A crude solid 24 is placed directly in the sublimation chamber 10 and heated under a vaccum applied via a vacuum port 26. Under supplied heat and sub-atmospheric pressure, a fraction of the crude solid 24 may vaporize and condense as a purified material on an actively cooled surface 28 of the coolant line assembly 12, leaving any solid residue inside chamber 10. This cooled surface 28 is often termed a cold finger, is often of limited surface area, and is vertically oriented in FIG. 1. Once heating ceases and the vacuum is released, the joint member 18 can be detached and any purified material can be collected from the cooled surface 28.
The present invention relates to an improved Vacuum Sublimation Module (VSM) comprising a singular combination of design elements to achieve a practical and convenient purification of certain solid materials through factors such as vapor flow directionality, sublimate collection, gas-seal efficiency, pressure-temperature control, power consumption, mechanical reliability, transparency, and user-friendliness.